1. Field of the Invention
The present invention generally relates to a liquid crystal display panel, and more particularly to a liquid crystal display panel having a touch function.
2. Description of the Related Art
Referring to FIG. 1, a conventional liquid crystal display panel 10 includes a data printed circuit board (data PCB) 32, a plurality of data tape carrier package (date TCP) 34, a gate printed circuit board (gate PCB) 36, and a plurality of gate tape carrier package (gate TCP) 38. Each date TCP 34 is electrically connected to the data PCB 32 and data lines of the liquid crystal display panel 10 and includes a data driver 42. Each gate TCP 38 is electrically connected to the gate PCB 36 and gate lines of the liquid crystal display panel 10 and includes a gate driver 44.
The liquid crystal display panel 10 is formed by combining a thin film transistor (TFT) substrate 52 with a color filter (CF) substrate 54. There is a gap between the TFT substrate 52 and the CF substrate 54, wherein a liquid crystal layer is filled in the gap.
According to the driving principle of the liquid crystal display panel, the liquid crystal display panel is provided with a plurality of gate lines and data lines, wherein the gate lines are adapted to switch on or off gate electrodes of thin film transistors (TFTs), and the data lines are adapted to transmit data signals. The PCB is provided with a timing controller (T-con), DC/DC converter and control lines. Generally, the PCB is designed to transmit driving signals and control signals of data drivers and gate drivers to the data lines and gate lines of the liquid crystal display panel respectively.
Generally, after a touch panel and a liquid crystal display panel are manufactured independently, the liquid crystal display device having a touch function is formed by assembling the touch panel to the liquid crystal display panel. Conventional touch panel can be a resistance type, an electromagnetism type or a capacitance type touch panel. The resistance type touch panel detects a coordinate of a touch point by sensing resistance. In other words, the coordinate of the touch point is acquired by measuring a resistance variation resulted from the touch point at the relative regions of the touch panel. The electromagnetism type touch panel detects a position of a touch point corresponding to a surface of the touch panel by sensing electromagnetism or transmitting and receiving electromagnetism. The capacitance type touch panel detects a coordinate of a touch point by sensing capacitance. In other words, the coordinate of the touch point is acquired by measuring a capacitance variation resulted from the touch point at the relative regions of the touch panel.
In addition, a touch component and a display component are currently integrated and manufactured to the same panel so as to form a liquid crystal display panel having a touch function. Referring to FIG. 2, Taiwan Patent Application Number 09145375 discloses that a conventional optical liquid crystal display panel 10 includes a plurality of gate lines 12 laterally disposed, a plurality of data lines 14 longitudinally disposed, and a plurality of first and second pixels 16, 18. The first and second pixels 16, 18 is respectively constituted by the enclosure of two adjacent gate lines 12 and two adjacent data lines 14. The first pixel 16 includes a first TFT 20 which has a gate electrode electrically connected to the gate line 12, a source electrode electrically connected to the data line 14, and a drain electrode electrically connected to a pixel electrode (not shown). The second pixel 18 includes second and third TFTs 22, 24 which respectively has a gate electrode electrically connected to two adjacent gate lines 12. The second TFT 22 further has a source electrode electrically connected to one of two adjacent data line 14, and a drain electrode electrically connected to a pixel electrode (not shown). The third TFT 24 further has a source electrode and a drain electrode electrically connected to an optical sensor 26 and a readout line 28 respectively. Generally, the optical sensor 26 is a fourth TFT which has a gate electrode and a source electrode electrically connected to a bias line 30 having constant pressure simultaneously, and a drain electrode electrically connected to the source electrode of the third TFT 24. When the optical sensor 26 is illuminated by an external light, the optical sensor 26 can generate an optical current acted as an optical signal.
Referring to FIG. 3, after the optical signal is read by the third TFT 24, the optical signal is transmitted to a signal processor 40 through the readout line 28 and a fan-out line 46 so as to detect a coordinate of a touch point positioned at the liquid crystal display panel 10. There are fan-out lines 46 formed between the readout lines 28 and the signal processor 40 for electrically connecting the readout lines 28 to the signal processor 40.
However, the gate TCP 38 in the prior art is not designed with conductive lines corresponding to the fan-out lines 46, and thus the readout lines 28 must be electrically connected to the signal processor 40 through an additional flexible printed circuit (FPC) board 48. Therefore, the FPC board 48 can increase the manufacture time and cost. Furthermore, the fan-out lines 46 also occupy some area of the liquid crystal display panel 10 so as to reduce the area of display region of the liquid crystal display panel 10.
Accordingly, there exists a need for a liquid crystal display panel having a touch function capable of solving the above-mentioned problems.